Valve for rock drills



April 17, 1928.

W. A. SMITH, JR

VALVE FOR ROCK DRILLS Filed Dec. 1. 1926 INVENTOR. m 151m (b J Patented Apr. 17, 1928.

UNITED STATES PATENT OFFICE.

WILLIAM A. SMITH, JR., 013 NEW YORK, N. Y., ASSIGNOR TO INGERSOLL-RAND CO]!- PANY, F JERSEY CITY, NEW JERSEY, A CORIPORATION OF NEW JERSEY.

VALVE FOR ROCK DRILL-S.

Application filed December This invention relates to rock'drills, but more particularly to. a distributing valve for fluid actuated rock drills of the hammer 7 and positive valve action.

its rearward end into which extends a Other objects will appear hereinafter.

The invention consists of'the features-of construction and arrangement of parts substantially as hereinafter described and claimed and illustrated in the accompanying drawings, in which Figure 1 is a sectional elevation of a portion of a rock drill showing the valve in one of its limiting positions, and

Figure 2 is a View similar to Figure 1, showing the valve in its other limiting position.

Referring to the drawings, A represents a cylinder having a reciprocatory hammer piston B. A drill steel C projects into the front end of the cylinder A to receive the blows of the hammer piston B and is guided by a head D which forms a closure for the front end of the cylinder.

At the rearward end of the cylinder A is disposed a valve chest designated generally by E. The valve chest E in this instance comprises a valve block F and front and rear plates G and H respectively. The front plate G interposed in this instance between thevalve block F and the cylinder A has a rearwardly extending boss J which fitsinto a recess K in the front end-of the valve block 1 F for the purpose of centralizing the valve block and the plate G with respect to each other. also acts as a closure for of the cylinder.

In the valve block F is formed a valve chamber L closed at its front end by the plate G and having an enlarged bore Oat projection P carried ply the plate H for holding the said plate in proper assembled relationship with respect to the valve block F.

Pressure fluid conveyed from any suitable source of supply (not shown) may be delivered to a passage Q in a back head R, and

the distribution of vsuch pressure fluid is effected by a distributing valve S having in this instance a. bore T of uniform diameter- In the present instance the plate G. the rearward end 1 It will be noted that the pressure fluid from both ends of the cylinder A is exhausted to 1, 1926. Serial No. 151,954.

formed an actuating surface U which is constantly exposed to pressure fluid for throwing the valve in a forwardly direction and an annular actuating face V of larger area than the surface U isformed at the front end of the valve to be'intermittently exposed to pressure for throwing the valve rearwardly. In the present instance the valve S carries a fla'nge W near 'its rearward end and the rearward face X of said flange constitutes an actuating face against which pressure fluid may intermittently act toassist the pressure 'fluid acting against the surface U for throwing the valve S forwardly.

Communication betweenthe front end of the valve chamber L and the rearward end of the cylinder A is afforded-by a plurality of inlet passages Y through the boss J of the plate G, and pressure fluid to the front end of the cylinder A is conveyed thereto through a passage Z in the cylinder A, the plate G and the valve block F, said passage Z communicating with the rearward end of the valve chamber L through a port 6 in the valve block F. The passage Z also serves as an exhaust passage for the pressure fluid from the front end of the cylinder A and communicates with the enlarged bore 0 through a port 0 controlled .by the flange W.

Leading from a point near the rearward end of the cylinder A is an exhaust passage 61 which leads to an annular port e near the front end of the valve chamber L for exhausting the. pressure fluid from the rearward end of the cylinder. The port e in the present instance is controlled by a flange f formed on the front end of the valve S.

the valve chamber and such exhaust of pressure fluid may pass therefrom to the atmosphere through an exhaust port g located be- .tween the port 6 and theenlarged bore 0 of the valve chamber. v

In order to convey live pressure fluid from the cylinder A to the rearward end of the enlarged bore 0 to act against the actuating face X, a passage 72. is formed in the cylinder A and the valve block F and is controlled only'by the piston B. Such pressure fluid may be exhausted from the rearward end of flow through However,

through the inlet passage ber into the rearward end of the cylinder A.

In the operation of the drill with the parts in the positions illustrated in Figure 1, pressure fluid entering the passage Qjwill the valve S and through the front end of the chamber L and the inlet passages Y into the rearward endof the cylinder'A to impel the piston B forwardly against the-drill steel. 1

Slightly prior to the instant of delivery of the blow against the drill steel the passage h will be uncovered by the piston B and pressure fluid will then flow through said passage hto the rearward end of the bore 0- and acting against the actuating face X will augment the pressure fluidacting against the actuating surface U to throw the valve S forwardly to the position shown in Figure 2.

.As the valve is thrown forwardly the flange f will uncover the port 6 thus providing an escape for the pressure fluid in the rearward end of the cylinder through the passage (1, the port 6 and thence through the exhaust port 9 to the atmosphere.

With the valve thrown forwardly pressure fluid will flow over the rearward end of the valve through the port b, thence Z to the front end of the cylinder to drive the piston B rear wardly.'

During a portion of the rearward stroke of the piston B the atmos heric air together with the pressure fluid lea ing into the rearward end of .the cylinder through the conduit is will be expelled through the passage (1 and the exhaust port to the atmosphere. after the piston B overruns the passage d the air will be compressed in the rearward end of the cylinder by the piston and acting against the actuating surface will again throw the valve rearwardly to its initial position, thus completing the cycle of operations.

I claim: I

1. In a fluid actuated rock drill, the combination of a cylinder, a hammer piston in the cylinder, a valve chest havinga valve chamber closed at its front end, inlet. passages leading from the valve chamber' to the cylinder, a valve in the valve chamber having a bore therethrough, said bore heing'in constant communication with a source of pressure fluid supply, an actuating sifrface on the rearward end of the valve constantly exposed to live pressure fluid for throwing the valve forwardly, a flange on the valve having an actuating surface intermittently exposed to live pressure fluid to assist in throwing the valve forwardly, said flange controlling the exhaust of fluid from the front end of the cylinder, an annular actuating surface at the termittently exposed to air compressed by the piston for throwing the valve rearwar and a passage in the cylinder and the valve chest for conveying pressure fluid to the actuating face on-the flange, said passage being controlled only by the piston.

2. In a fluid actuated rock drill, the combination of a cylinder, a'hammer piston in the cylinder, a valve chest having a valve chamber, front and rear inlet passages leading from the valve chamberto the cylinder, an'exhaust passage leading from the valve chamber to the atmosphere, a valve controlling the inlet and exhaust passages, said valve being hollow to convey pressure fluid therethrough to the rear inlet passage, a rear actuating surface on the valve constantly exposed to pressure fluid for throwing the valve forwardly, a flange" near the rearward end of the valve having an actuating face intermittently exposed to pressure fluid to the valve forwardly, an the front end of the exposed to air com pressed by the piston for throwing the valve rearwardly, a kicker passage in the cylinder and valve chest forconveying pressure fluid from the cylinder to the actuating surface 'on the flange, said kicker passage being controlled by the piston, and a passage 1n the assist in throwing actuating surface at valve intermittently.

V end of the valve chest constantly admitting dly,

pressure fluid to the rearward end of the 2 cylinder to augment the compression for throwing the valve rearwardly.

In testimony whereof I have signed this specification.

WILLIAM A. SMITH, J n. 

